54.0 million over 65
48.9 million on disability
328.2 million total population
185.8 million people employed at 56.6% employment
128.1 million people not employed (including children)
54 million people not employed, but marginally employable (max income is $1,260 per month if on disability and $18,240/yr when retired)
In any case, under-employment is still a bigger issue than unemployment.
That said, the real figures are still startling. They represents 4.4% of the US worker population but some states rely incredibly heavily on the program.
Alabama - 8.0% of the population
Arkansas - 7.9% of the population
Kentucky - 7.6% of the population
Maine - 7.4% of the population
Mississippi - 7.5% of the population
West Virginia - 8.6% of the population